What is more likely to revolutionise physics - spending $20bn on an incremental increase in collider energies, on spending $20bn funding a new generation of PhDs and postdocs exploring quantum gravity fundamentals?
At this point practical HEP shows every signs of being a boondoggle. There are plenty of hard theoretical questions that haven't been answered, but with a few exceptions they're outside of the mainstream. Research into them has been actively discouraged, except at a few locations.
Physics doesn't need more hardware, it needs more ideas - more intellectual diversity, and more creativity.
Often not, because you don't know what areas to choose. Having a big, hard goal to solve usually requires building pieces to solve the problem, and these pieces end up being useful in themselves. Plus the big goal is often achieved.
Mankind could have done a lot of the stuff discovered along the way to big goals, but didn't, until the big goals were attempted.
Plus, it's often easier to get funding as a nation-state for big goals. Little side projects are often not individually worth chasing. The internet is a good example - it could have been done by industry before the govt decided to chase it as a piece of a big goal.
Electrons were useful, because they have long lifetimes, are easy to make, and interact well. Higgs bosons are unlikely to be useful as technology ever since they are so ephermeral. And they're certainly not giving immediate benefits.
Nobody is sure about anything. Nobody denies that high-energy physics might one day bring great things. The problem is cost. Other areas of science are much more likely to bring great things with far less money. If tens of billions are to be spent on a bigger microscope, let it be one that will give us better solar panels, or a direct treatment for viruses. Polishing the details of the standard model can wait.
Things are not quite that bad, but the case is weaker now than it has ever been before.
Why should society at this day and time then plow millions of man hours and raw materials into proving it literally?
Perhaps when nanotechnology or AI is able to be put to the task, those peoples can then build a very specific machine to prove very specific questions
But this is throwing spaghetti at the wall for what to us will be a moment of excitement then having no clue how to make use of it and a big mess to clean up
